Variable pitch and reversible propeller



F. T. IRGENS 3,288,228

VARIABLE PITCH AND REVERSIBLE PROPELLER 2 Sheets-Sheet l Nov. 29, 1966 Filed May 28, 1965 as a /&

. 47 4 a 48 52 i W a2 INVENTOR.

fi/v/v Z' legs/vs AI'I'OE/VEYS United States Patent 3,288,228 VARIABLE PITCH AND REVERSIBLE PROPELLER Finn T. Irgens, Milwaukee, Wis., assignor to Outboard Marine Corporation, Wankegan, 111., a corporation of Delaware Filed May 28, 1965, Ser. No. 459,753 8 Claims. (Cl. 170160.43)

This invention relates to propellers and, more particularly, to variable pitch and reversible boat propellers.

The principal object of the present invention is to provide a propeller having a pitch which can be adjusted through a range of at least about 90 degrees while the propeller is in operation. Thus, the propeller pitch can be completely reversed to afford a complete reversal thrust from full forward thrust to full reverse thrust, or vice versa, or the pitch can be adjusted to an intermediate position affording any desired amount of forward or reverse thrust.

In accordance with the invention, the propeller generally includes a number of blades mounted on a hub carried by the end of a propeller shaft. Each blade includes a base portion having thereon a gear segment. The hub includes a cavity and means for rotatably mounting each of the base portions on the hub with the gear segments disposed within the cavity. Other means is carried by the hub and is cooperable with the respective gear segments of the blades for affording angular rotation of the blades relative to the hub so as to afford thrust reversal.

Other objects and advantages will become apparent in the following description and accompanying drawings in which:

FIGURE 1 is a fragmentary plan view with parts broken away and removed, showing a propeller in accordance with the present invention;

FIGURE 2 is a sectional view taken along the line 22 of FIGURE 1;

FIGURE 3 is a sectional view taken along the line 33 of FIGURE 1;

FIGURE 4 is a reduced, side elevational view of the propeller of the present invention;

FIGURE .5 is a fragmentary plan view similar to FIG- URE 1 illustrating a modified form of the present invention; and

FIGURE 6 is a sectional view taken along the line 6-6 of FIGURE 1.

Referring now to the drawings and more particularly to FIGURES 1 and 2, the propeller is broadly identified by the numeral 10 and generally comprises a pair of blades 12 and a hub 14 having means thereon (hereinafter to be described) for pivotally mounting the blades 12 for rotation relative to the hub 14 about an axis transverse to the intended axis of rotation of the hub 14.

The hub 14 includes an interior defining an irregularly shaped cavity 16 and a pair of guideways 18 disposed on the interior wall of the hub 14. The guideways 18 are parallel to each other and to the intended axis of rotation of the hub 14. The hub 14 has a first end 20 which includes interiorly disposed female threads 22 and has a second end 24 which includes a plate 26 removably mounted thereon by means of screws 28.

Said means for pivotally mounting the blades 12 on the hub 14 comprises a pair of axially spaced and oppositely disposed first radial bores 30 extending through the wall of hub 14. Each of the bores 30 includes a bearing portion 32 and an adjacent counter-bored portion 34 providing a flat, circular land 36 between the bearing portion 32 and the counter-bored portion 34.

The propeller blades 12 each respectively include a blade portion 37 and a base portion 38 which is disposed in the associated first radial bores 30 for affording blade rotation relative to the hub 14 about respective base portion axes 39 (see FIG. 4). The blade portions 37 are oifset from the base portion axes 39, as shown in FIG. 4, to afford locating the blade portions more or less in the single plane (indicated by the numeral 43 in FIG. 4) when the blades are arranged for maximum rearward thrust.

In the disclosed construction, each of the base portions 38 includes a blade hub 40 and a stub shaft or spindle 42 extending from the blade hub 40. The shaft 42 is of smaller diameter than blade hub 40, thus providing a shoulder 44 between blade hub 40 and shaft 42. The shaft 42 includes a gear segment 46 which is spaced from shoulder 44 and which has a face portion 47. The gear segment 46 may be of integral construction with shaft 42, as shown in the disclosed construction, or it may comprise a separate gear fixed to shaft 42. The shaft 42 has an end portion 48 of smaller diameter extending from face 47 of gear segment 46. The end portion 48 includes internal threads 49.

The propeller blades 12 are respectively disposed in the first radial bores 30 with the blade hubs 40 fitting in the counter-bored portions 34 and with the shafts 42 journally received in bearing portions 32. The gear segments 46 extend within the cavity 16 and are generally co-planar with and between the guideways 18.

Referring to FIGURE 3, means are provided for preventing radial movement of blades 12 with respect to hub 14. In the preferred embodiment, such means comprises a pair of second radial bores 50 in the wall of hub 14 in respectively opposed and concentric relation to the first radial bores 30. Each of the second radial bores 50 includes a first portion 52 and a counter-bored portion 54 providing a flat, circular land 56 between the first portion 52 and the counter-bored portion 54. The end portions 48 are respectively received in the first portions 52 of radial bores 50 and fit generally flush with the lands 56. The internal threads 49 respectively receive screws 62 having heads 64 which abut the lands 56 in order to prevent radial movement in either direction and the shoulder 44 abuts land 36.

To assure a proper alignment of gear segment 46 with respect to guideways 18, a lip 66 is disposed on the interior wall of hub 14 to engage face 47 of gear segment 46.

The hub 12 is removably carried by threaded attachment to a hollow propeller shaft 68 for rotation of ihub 12 therewith. The intended axis of the hub 12 is the axis of propeller shaft 68. The propeller shaft 68 also includes a central, longitudinal .bore 76 for reasons to be explained hereinafter.

Means are provided for angularly rotating the blades 12 with respect to the hub 14 through a range of at least about 90 degrees. In the preferred embodiment of the present invention, such means comprises a U-shaped rack 78 slidably disposed in the guideways 18. The U-shaped rack 78 includes a shorter arm 80 having a portion including thereon gear teeth 82 and a longer arm 84 having a portion including thereon gear teeth 86. The respective arms 80 and 84 are disposed in guideways 1'8 with the gear teeth 82 and 86 separately engaging the respective gear segments 46. The arms 80 and 84 including the portions having thereon gear teeth 82 and 86 are of sufiicient length whereby axial movement of rack 78 affords rotation of blades 12 through an angle of about 90 degrees. As shown in FIGURE 2, the arms 80 and 84 are of differing length, and the gear segment 46 only partially circumscribes the stub shaft 42 to afford separate engagernent with the respective gear teeth 82 and 86, thereby Patented Nov. 29, 1966 preventing simultaneous engagement of the gear teeth of one arm with both gear segments to cause a lock-up of the propeller 10.

In the preferred embodiment, the gear segments 46 are shown enga-geable with each other, and the gear teeth 82 and 86 of the arms 80 and 84 respectively engage said gear segments. However, in an alternative construction, this invention is operable with the gear segments not engageable with each other and the gear teeth of the rack arms separately engaging the gear segments. However, with the gear segments 46 enga-geable with each other, an added degree of stability and less spacing between the blades 12 is provided. This invention also contemplates the use of a rack means having a single arm with teeth engaging one of the meshed gear segments 46 when the segments 46 are in meshed engagement. In this event, use of a ingle guideway 18 is sufficient.

As discussed above, axial movement of rack 78 affords relative movement of blades 12 with respect to hub 14. Means are provided for affording such axial movement of the rack 78. In the preferred embodiment of the present invention, such means comprises a control rod 88 received in the bore 76 with one end 90 connected with the rack 78. The other end of rod 88 is connected by a suitable linka-ge to a remote actuating lever (not shown) operable by the driver. Axial movement of control rod 88 in either direction will reciprocally move rack 78 and afford angular rotation of blades 12 through an angular range suflicient to provide a complete reversal of the propeller blades 12 to afford complete reversal between forward thrust and reverse thrust. The rack 78 can be disposed in any intermediate position to afford any range between zero and maximum of forward or reverse thrust.

The respective base portions 38 of the propeller blades 12 are sealed with respect to hub 14 by means of O-rings 96 and 97 received in respective circumferential grooves 98 and 99 on shafts 42 and end portions 48.

As shown in FIGURES 1 through 4, the first radial bores 30 carrying the blades 12 are axially spaced from each other, slightly offsetting the blades 12 from each other. To afford oppositely disposed propeller blades that are generally axially aligned with each other, the propeller is desirably constructed as shown in FIGURES and 6. The blades 100 include base portions 102 which are inclined or acutely angularly related to the center line or axis 103 of the blades 100 with the center line of each base portion 102 intersecting the blade axis 103 at point A, as shown in FIGURE 6. Therefore, when the blades 100 are rotated with respect to the hub 104, the point A remains fixed and always lies on the axis 103 of the blades 100.

In the embodiment shown in FIGURES 5 and 6, the generally hollow hub 104 includes means for pivotally mounting the base portions 102 thereon for rotation of the blades 100 with respect to the hub 104 about an axis angularly related to the intended axis of rotation of the hub 104. In the disclosed construction, said means comprises a pair of axially spaced and oppositely disposed parallel first radial bores 106 extending through the wall of the hub 104 defining respective bearing surfaces. Each of the bores 106 is acutely angularly related to an axis transverse to the intended axis of rotation of the hub 104 in the same acute relationship as the base portions 102 are to the blades 100.

The base portions 102 include first portions or spindles 108 which are received in the respective first radial bores 106 to afford rotational movement of the blade 100 with respect to the hub 104. The base portions 102 also include stub shafts 110 which extend from first portions 108 and which are of smaller diameter than the first portions 108 to provide a fiat circular land 112. The stub shafts 110 include therein gear segments 114 which are spaced from land 112 and which have faces 116. The shafts 110 also include internally threaded end portions 118 extending from the faces 116 of the gear segments 114.

Referring now to FIGURE 5, wherein the blades are shown for full forward driving position, assuming that the propeller is turned counter-clockwise when looking from the rear of the propeller, i.e., from the right end of FIG- URE 5, means are provided for preventing radial movement of the blades with respect to the hub 104. Said means comprises second radial bores 120 opposite of and concentric with the first radial bores 106. The end portions 118 of the stub shafts are respectively received in the second radial bores 120 with the portions 122 of the interior wall of hub 104 respectively abutting the faces 116 of the gear segments 114. The second radial bores 120 have respective counter-bored portions 124 defining respective flat, circular lands 126 in each of the second radial bores 120. Screws 128 are threadedly received in the respective end portions 118 with the heads of screws 128 abutting the respective lands 126 and securely holding portions 122 against the respective faces 116 of gear segments 114 to prevent movement of the blades 100 in either direction along the axis of the base portions 102.

The hub 104 includes on the interior thereof parallel guideways 130 which are offset as shown in FIGURE 6 and which slidably receive a rack 132. The rack 132 has a longer arm 134 including a portion having there-on angled gear teeth 136, and a shorter arm 138 including a portion having thereon angled gear teeth 140, which gear teeth 136 and 140 respectively engage the gear segments 114. The arms 134 and 138 are of sufficient length whereby axial movement of the rack 132 affords rotation of the blades 100 through a range of at least about 90 degrees.

The hub 104 is suitably carried by the end of a propeller shaft 142 having a longitudinal bore 143. A control rod 144 is carried in bore 143 and is suitably fastened to the rack means 132. Axial movement of the control rod in either direction affords reciprocal movement of the rack to provide a rotation of the blades 100 with respect to the hub through a range of at least about 90 degrees.

The respective base portions 102 are sealed with respect to the hub 104 by means of O-rings 146 and 147 in respective circumferential grooves 148 and 149 disposed on first portions 108 and end portions 118.

The embodiments shown in FIGURES 5 and 6 afford the advantage of having better mechanical balance because the effective parts or driving surfaces of the blades are directly opposite from each other in the forward driving position of the propeller blades, as shown in FIGURE 5, and because each blade works in an equivalent amount of water.

A propeller in accordance with the invention affords the advantages of having a hub which is smaller in size and which can be filled with grease and easily sealed. In addition, a propeller constructed in accordance with the invention affords propeller blades spindles which are strong and which are disposed in bearings which are generously spaced from one another.

Also, if desired, various of the components of a propeller in accordance with the invention can be easily arranged to afford rotation of the blades through a range of more than 90 degrees. This is desirable if the blades are intended to feather completely behind the stern post on sailboats so as not to drag when not in operation.

Various of the features of the invention are set forth in the following claims.

What is claimed is:

1. An adjustable pitch propeller comprising a pair of blades each having a blade portion and a base portion including thereon a gear segment and having an axis about which said blade is rotatable, a hub having means mounting said base portions on said hub in parallel relation to each other spaced axially of said hub for rotation of said blades with respect to said hub and so that said blade portions lie generally in a common plane in one condition of operation, and rack means cooperable with said gear segments for angularly rotating said blades about said base portion axes.

2. An adjustable pitch propeller comprising a pair of blades each having a blade portion and a hub portion having therein a gear segment and including an axis of rotation, said blade portions being ofiset from said axes of rotation, a hub having means mounting said base portions on said hub in spaced relation to each other axially of said hub for rotation of said blades with respect to said hub and so that said blade portions lie generally in a common plane in one condition of operation, and a rack slidably carried by said hub in engagement with said gear segments for angularly rotating said blades about said base portion axes.

3. An adjustable pitch propeller comprising a pair of blades each having a blade portion and a hub portion having thereon a gear segment and including an axis of rotation, said blade portions being offset from said axes of rotation, a hub having means mounting said base portions on said hub in spaced relation to each other axially of said hub for rotation of said blades with respect to said hub and with said gear segments in meshing engagement with each other and so that said blade portions lie enerally in a common plane in one condition of operation, and a U-shaped rack slidably carried by said hub in engagement with said gear segments for angularly rotating said blades about said base portion axes.

4. An adjustable pitch propeller comprising a hollow shaft, a series of blades having axes, each of said blades including a base portion having thereon gear segments and having an axis about which said blade is rotatable, each of said base portion axes being angularly related to the corresponding blade axis, a hub carried by the end of said shaft for rotation with said shaft and having means for rotatably mounting said base portions of said blades in said hub in parallel relation to each other and in angular relation to the axis of intended rotation of said hub and with said gear segments of said blades meshed with each other, and a rack slidably disposed in said hub and engageable with at least one of said gear segments of said respective base portions, said rack means being movable in a direction along the axis of rotation of said hub.

5. An adjustable pitch propeller comprising a pair of oppositely disposed blades having axes, each of said blades including a base portion having thereon an integral gear segment and having an axis about which the blade is rotatable, each of said base portion axes being angularly related to its corresponding blade axis, a hub having means for rotatably mounting said base portions of said blades in said hub in parallel relation to each other and in acute angular relation to the axis of intended rotation of said hub, and a U-shaped rack slidably disposed in said hub and engageable with said gear segments of said respective base portions, said rack being movable in a direction along the axis of rotation of said hub.

6. An adjustable pitch propeller in accordance with claim 5 wherein said respective gear segments are meshed with each other and said U-shaped rack has parallel legs respectively engaged with said gear segments.

7. An adjustable pitch propeller comprising a hollow shaft, a pair of oppositely disposed blades each having an axis, each of said blades including a base portion having an integral gear segment thereon and having an axis about which the blade is rotatable, each of said base portion axes being angularly related to the corresponding blade axis, and a hub carried by the end of said shaft for rotation therewith and having axially spaced and oppositely disposed means for rotatably mounting said base portions of said propeller blades in acute angular relation to the intended axis of rotation of said shaft with the corresponding gear segments engaged with each other, a U-shaped rack slidably carried by said hub and having parallel leg portions of unequal length including teeth thereon, said leg portions being engageable with said respective gear segments, and a control rod disposed in said hollow shaft and connected to said rack for reciprocally moving said rack along the intended axis of said hub to provide angular rotation of said blade with respect to said hub and through a range of about degrees.

8. An adjustable pitch propeller comprising a hollow propeller shaft, a hollow propeller hub carried by said shaft and having a pair of guideways on the interior wall of said hub and a pair of oppositely disposed and axiallyspaced first bores extending through the wall of said hub to define respective bearing surfaces, the axis of each of said bores being parallel to each other and acutely angularly related to the axis of said hub, a pair of blades each including a base portion having an axis angularly related to said blade and having a first portion, a stub shaft including thereon a gear segment having end faces and an internally threaded end portion extending from said gear segment, said first portions being respectively received in said first radial bores with said gear segments interiorly disposed between the Walls of said bore and engaged with each other for rotation of said blades with respect to said hub, means for preventing radial movement of said blades with respect to said propeller hu-b comprising respective second radial bores oppositely disposed with respect to said first radial bores having a bearing portion and a counter-bored portion providing a flat, circular land between said first portion and said counter-bored portion, said end portions respectively fitting into said bearing portions of said respective second bores with said end portions fitting flush with said lands in said second bores and with said end faces of said gear segments respectively con tacting the interior walls of the propeller hub surrounding said respective second bores, and screws respectively threadedly received in each of said end portions and having heads abutting said lands of said respective second bores for preventing radial movement of said blades with respect to said propeller hub, a U-shaped rack slidably carried in said guideways and including a shorter arm having angled teeth engaged with one of said gear segments and a longer arm having angled teeth engaged with the other of said gear segments, and a control rod carried by said hollow shaft and connected to said rack for reciprocally moving said rack in a direction along the intended axis of rotation of said hub to provide angular rotation of said blades with respect to said propeller hub through a range of about 90 degrees.

References Cited by the Examiner UNITED STATES PATENTS MARTIN P. SCHWADRON, Primary Examiner.

SAMUEL LEVINE, Examiner.

E. A. POWELL, JR., Assistant Examiner. 

1. AN ADJUSTABLE PITCH PROPELLER COMPRISING A PAIR OF BLADES EACH HAVING A BLADE PORTION AND A BASE PORTION INCLUDING THEREON A GEAR SEGMENT AND HAVING AN AXIS ABOUT WHICH SAID BLADE IS ROTATABLE, A HUB HAVING MEANS MOUNTING SAID BASE PORTIONS ON SAID HUB IN PARALLEL RELATION TO EACH OTHER SPACED AXIALLY OF SAID HUB FOR ROTATION OF SAID BLADES WITH RESPECT TO SAID HUB AND SO THAT SAID BLADE PORTIONS LIE GENERALLY IN A COMMON PLANE IN ONE CONDITION OF OPERATION, AND RACK MEANS COOPERABLE WITH SAID GEAR SEGMENTS FOR ANGULARLY ROTATING SAID BLADES ABOUT SAID BASE PORTION AXES. 